Presentation on theme: "Outline This Presentation contains slides appropriate for all the sections of the activity. – White slides are included (but hidden from the Slideshow)"— Presentation transcript:
Outline This Presentation contains slides appropriate for all the sections of the activity. – White slides are included (but hidden from the Slideshow) as bookmarks. – You will need to show or hide slides according to which sections you are using. – Note that some slides include animations – it is recommended that you view the Slideshow itself before presenting it. Multiwavelength Astronomy
Electromagnetic radiation We describe EM radiation by: –Frequency –Wavelength Light travels at: –300,000,000 m/s Wavelength
Multiwavelength Astronomy The Electromagnetic Spectrum The EM spectrum is (arbitrarily) split up:
Black Body Radiation (A-level Only) Multiwavelength Astronomy
“Black Body” radiation A black body is a perfect emitter and absorber of radiation –It emits and absorbs radiation with a particular “spectrum” –The shape of the spectrum is always the same, but the peak wavelength changes with temperature. –But not all objects are black bodies. –Atoms, molecules and electrons emit radiation with a different spectrum – this is called “non-thermal radiation”
Multiwavelength Astronomy Black Body Temperature The wavelength with most emission is related to the black body temperature Max. wavelength (m) x Temperature (K) = Wien’s Displacement Constant max x T = 0.0029 K.m T = 0.0029 / max
Spectral Regimes Fill in the wavelength summary table (Note that slides have animations) Multiwavelength Astronomy
The Spectral regimes Fill in the Wavelength Summary Table You will need this later.
Multiwavelength Astronomy Telescope sizes The best possible resolution a telescope can see depends on the size of the mirror and the wavelength of light it is measuring Resolution (deg) ~ 60 x Wavelength (m) Diameter of mirror (m) ~ 60 x D 1 degree = 60 arcminutes ; 1 arcminute = 60 arcseconds 1 degree = 3600 arcseconds
Multiwavelength Astronomy Examples of telescopes Hubble Space Telescope –D=2.2 m ; =500 nm – =2.3x10 -7 degrees = 0.8 milliarcsecond Lovell Telescope, Jodrell Bank –D=76 m ; =1 m – =0.75 degrees Spitzer Space Telescope –D=0.7 m ; =100 m – =1.4x10 -4 degrees = 0.5 arcseconds Herschel –D=3.5 m ; =100 m – =2.9x10 -5 degrees = 0.1 arcseconds
Herschel (+ Planck) Intro Launch video requires the video file “HP_launch.wmv” (may need to be re-linked) Multiwavelength Astronomy
The Atmosphere The Earth’s atmosphere blocks radiation at some wavelengths –This is why many telescope are in space
Wavelength Matching activity Distribute question sheet and images Suggested group size: 2-3 Multiwavelength Astronomy
Match up the wavelengths There are 12 objects provided with images in visible light You have to match up the other wavelengths for each object –Some are quite straightforward… –Others are not! There is a prize for the highest score!
What have we learned? To understand the Universe fully, we need to observe at multiple wavelengths The temperature of an object can affect the wavelength it emits most radiation at. Some wavelengths are blocked by the Earth’s atmosphere and must be observed from space
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